Alonzo Christian, 45, was arrested Friday morning, the Sheriff's Department said. He, along with Deon Carter, 29, and Travaris Christian, 20, have been charged with capital murder in connection with the slayings, investigators said. All three men are also charged with house burglary, felony child abuse and conspiracy, the Sheriff's Department said.

The bodies of Robert Carter, 26, and his fiancée, Renitra Lee Mark, 24, were found inside their house on Timberidge Road on Wednesday, the Hinds County Sheriff's Department said. The county coroner said the couple, who had both been shot, had been dead for about 48 hours.

The couple's 7-month-old son was left alone with the bodies, the Sheriff's Department said. The baby was about 10 feet away from his father's body, Deputy Vincent Williams said. Marks' body was found in a bedroom. Williams said it looked like she had tried to get away from her attackers.

Deputy Chris Smith was the third deputy to arrive at the scene on Wednesday. He said while on his way to the call he heard there was a baby that had not been attended to for several days.

"I walked in, saw the first subject lying on the ground, obviously deceased. I looked over to the left and in front of a big screen TV with the cartoons playing was the baby, just crying uncontrollably. I didn't worry about too much else," Smith said. "The baby was upset, rightfully so. He had been alone, sitting on the ground. The baby couldn't move. The baby couldn't roll over. The baby couldn't do anything. He was just in that position for two days."

Smith said he found the boy's bedroom and changed his diaper and soiled clothes.

"I have an 18-month-old little girl at home and so I just treated the little boy as if he were my own and took care of him," Smith said. "I went to the refrigerator and found that I was lucky enough that mama had made a couple extra bottles. I went ahead and gave the child one of the bottles immediately."

The child was placed in Department of Human Services custody and hospitalized for dehydration. Family members said he is now with Mark's mother.